Is all Nylon SLS the same quality?

Quality is not a word that you often hear associated with 3D printing, but it is a key question when you are looking to get the best results from the technology.

If you are comparing quotes, it’s important to be confident that you’re making a like for like comparison and asking questions about some of the factors below will help you. Nylon SLS is more than just your average 3D printed plastic. It can really perform in lots of different ways and it deserves to be produced at its best.

There are 7 main factors that determine the quality of Nylon SLS 3D printed parts.

1. The Machine Manufacturer

There are various industrial 3D printer manufacturers who produce machines that produce the material that is widely known as Nylon SLS, Strong and Flexible, PA2200 or Polyamide (PA).

D2W did extensive research before investing in our Nylon SLS technology, and we still believe that the parts produced by EOS (Electro Optical Systems) 3D Printers are both superior in finish and material properties. Some of our clients use us specifically because they know that we use EOS technology only.

2. The Layer Thickness

All Nylon SLS printers allow you to set different layer heights. Selecting thicker layer heights means that parts are built faster, but by doing this, it will significantly effect the quality of your part.

At D2W we never adjust layer thickness on any of our machines and all of our Nylon SLS is produced at the optimum 0.1mm layer thickness. We never compromise quality for speed.

3. Parameter Settings

These are primarily the settings that define the speed, power and pathway of the laser. These settings play an integral role in the speed and quality of parts made.

At D2W we always choose a laser path, that will not only provide you with the best surface quality, but in conjunction with the 0.1mm layer thickness, it will again also increase the tensile strength. Our laser will travel further, and work harder to create a better part for you.

4. The Powder Ratio

A critical issue relating to the quality of Nylon SLS is the powder ratio used. The material for commercial Nylon SLS prints is a blend of new and recycled PA2200 powder. To achieve the best part quality and material performance, EOS recommend a powder ratio of 1:1. This ratio can of course be adjusted, and given the price of the Nylon powder, it can be tempting to begin adjusting this ratio to make it stretch further and increase margins. This decision will have a major effect on the quality of the parts. If the ratio is stretched, the parts will not be quite as white, and they will lose a lot of tensile strength. Accuracy will also be reduced and the ability to dye the parts consistently will be lost. It will also dramatically effect the success of investment casting your Nylon SLS parts. Yes, you can directly investment cast with good quality Nylon SLS!

Because of all these factors, we never doctor the powder ratio. To keep our optimum 1:1 ratios consistent, we have a proprietary mixing unit that simultaneously mixes and transports the powder directly to the machines.

5.The Size of Machine.

The size of machine has a bearing on the quality of the models produced as well. Smaller EOS Formiga P1 machines produce slightly better detail and strength. There are many reasons as to why this is the case but it’s mostly to do with the finer laser size, laser power and the scanning speed of the laser. The larger EOS P3 machines are designed with the primary intention to produce larger volumes quicker, which does have an impact on the part quality.

However, at D2W we have optimized our P3 to match the quality of our P1s as closely as possible. The quality of parts that we achieve from the P3, perform way above EOS’s part performance charts. If you are developing a product, we can ensure that the machine you develop your prototypes on, will also be the same machine that produces the product. Even though in many cases you will not find a difference between our fleet of machines, we still offer this as an option upon request.

6. The Production Team

No 3D printer runs itself. D2W have a highly skilled and experienced production team who not only organize and schedule all the requests and schedule printers, but they also work hard on keeping the machines highly calibrated to maintain consistency, efficiency and reliability. When working on production for you, if you have any queries, these people are also available to communicate with you. This kind of unmatched service plays a key role in the quality received as well.

It doesn’t end there, when the parts are removed from the machines, we are equipped with air guns and bead blasters to remove the powder from the sintered parts. This brings further accuracy and ensures that there is little to no powder stuck in cavities and corners.

7. Outsourcing

Do you know who has actually produced your Nylon SLS?

Some 3D printing services act purely as middle men and never have anything to do with the production of your parts and could answer very few of the questions posed above. You will clearly be paying a mark up on these types of service or getting inferior quality to cover the mark up.

Other bureaus that do have their own Nylon SLS 3D printers also regularly supply parts that they have outsourced (D2W occasionally provide some SLS to other bureaus) for any number of reasons.

We only ever outsource in emergencies such as when we have problems with the machines. On the rare occasions this happens, customers who are going to receive Nylon SLS from others, are informed.

Conclusions

When customers are looking at Nylon SLS for the first time, it’s imperative that their first impression is not compromised by any inferior production practices that they are not aware of. It’s a terrible loss of potential if a project is abandoned due to an unknown, yet avoidable lack of performance from the technology. We often produce parts that have previously been unachievable by other providers, despite them using the identical technology.

Many clients notice the difference between our Nylon SLS and others, and in many cases, once they use us, they never go anywhere else, as we achieve this performance time and again.

As an Industrial Design tutor states:

“some parts suppled by others are frankly a waste of time, money, and borderline fraudulent in my opinion. It’s a real shame when a student works hard on their CAD files only to find the person at the other end can’t use/maintain their machine so the resolution is poor and overpriced. I think it’s put a few students off using AM services, to be honest”

Beyond quality output, D2W also add value at the input stage, where our design team are always available to speak with customers and share their precious experience. Through these conversations, we understand your expectations of Nylon SLS parts.

Understanding your expectations and purpose, we are able to offer the best advice on all aspects of your files from performance, thicknesses and tolerances, to ways in which you might adjust the design to make it more economical. When we understand your objects, we care about them.

As one of our most ambitious clients explains:

“The ability to talk to and tap in to the experience of D2W’s professional design team, alongside their understanding of the importance of quality, allows for the previously unachievable to be much more possible”

As you can see, just like with anything else, quality and value within 3D printing is a combination of many different elements. D2W provide Nylon SLS of the highest quality by excelling in all of them.

Here are some examples of Nylon SLS projects and prints we've done for clients that are examples of our quality making their work outstanding.